METHOD AND APPARATUS FOR MANUFACTURING GLASS SUBSTRATE FOR MAGNETIC DISK, GLASS SUBSTRATE FOR MAGNETIC DISK, METHOD FOR MANUFACTURING MAGNETIC DISK, AND MAGNETIC DISK

摘要

PROBLEM TO BE SOLVED: To provide a glass substrate for a magnetic disk improved in reliability and durability by subjecting a chamfered portion to high accuracy mirror polishing with smaller machining allowance thereby preventing the occurrence of deposition of sodium and potassium, and a method for manufacturing the magnetic disk. SOLUTION: The grinding step of the chamfered portion includes steps of: simultaneously bringing grinding stones 21 into contact on the entire circumference of a circular ridge line 2e formed by one main surface 1a and outer peripheral surface 2a of the glass substrate 1 for the magnetic disk having a circular plate shape, and simultaneously pressing the circular ridge line 2e to the abutted grinding stones 21 over the entire circumference thereof to relatively move the grinding stones 21 and the glass substrate 21. Thereby, the chamfered portion 2b is ground between the one main surface 1a and outer peripheral end surface 2a of the glass substrate 1. The ground chamfered portion 2b is subjected to mirror polishing by repeating the processing similar to the grinding step by substituting polishing cloth for the grinding stones 21 in the polishing step. COPYRIGHT: (C)2008,JPO&INPIT